[PR71078] x / abs(x) -> copysign (1.0, x)

[Prathamesh Kulkarni]

Hi,
The attached patch tries to fix PR71078.
I am not sure if I have got the converts right.
I put (convert? @0) and (convert1? (abs @1))
to match for cases when operands's types may
be different from outermost type like in pr71078-3.c
test-case (included in patch).
Bootstrap+test in progress on x86_64-unknown-linux-gnu.

Thanks,
Prathamesh

diff --git a/gcc/match.pd b/gcc/match.pd
index 21bf617..6c3d6ec 100644
--- a/gcc/match.pd
+++ b/gcc/match.pd
@@ -391,6 +391,20 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
  (mult (abs@1 @0) @1)
  (mult @0 @0))
 
+/* PR71078: x / abs(x) -> copysign (1.0, x) */
+(simplify
+ (rdiv:C (convert? @0) (convert1? (abs @0)))
+  (if (FLOAT_TYPE_P (type)
+       && ! HONOR_NANS (type)
+       && ! HONOR_INFINITIES (type))
+   (switch
+    (if (type == float_type_node)
+     (BUILT_IN_COPYSIGNF { build_one_cst (type); } (convert @0)))
+    (if (type == double_type_node)
+     (BUILT_IN_COPYSIGN { build_one_cst (type); } (convert @0)))
+    (if (type == long_double_type_node)
+     (BUILT_IN_COPYSIGNL { build_one_cst (type); } (convert @0))))))
+
 /* cos(copysign(x, y)) -> cos(x).  Similarly for cosh.  */
 (for coss (COS COSH)
      copysigns (COPYSIGN)
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pr71078-1.c 
b/gcc/testsuite/gcc.dg/tree-ssa/pr71078-1.c
new file mode 100644
index 0000000..6204c14
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/pr71078-1.c
@@ -0,0 +1,29 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -ffast-math -fdump-tree-forwprop-details" } */
+
+#include <math.h>
+
+float f1(float x)
+{
+  float t1 = fabsf (x);
+  float t2 = x / t1;
+  return t2;
+}
+ 
+double f2(double x)
+{
+  double t1 = fabs (x);
+  double t2 = x / t1;
+  return t2;
+}
+
+long double f3 (long double x)
+{
+  long double t1 = fabsl (x);
+  long double t2 = x / t1;
+  return t2;
+}
+
+/* { dg-final { scan-tree-dump "__builtin_copysignf" "forwprop1" } } */
+/* { dg-final { scan-tree-dump "__builtin_copysign" "forwprop1" } } */
+/* { dg-final { scan-tree-dump "__builtin_copysignl" "forwprop1" } } */
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pr71078-2.c 
b/gcc/testsuite/gcc.dg/tree-ssa/pr71078-2.c
new file mode 100644
index 0000000..96485af
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/pr71078-2.c
@@ -0,0 +1,29 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -ffast-math -fdump-tree-forwprop-details" } */
+
+#include <math.h>
+
+float f1(float x)
+{
+  float t1 = fabsf (x);
+  float t2 = t1 / x; 
+  return t2;
+}
+ 
+double f2(double x)
+{
+  double t1 = fabs (x);
+  double t2 = t1 / x; 
+  return t2;
+}
+
+long double f3 (long double x)
+{
+  long double t1 = fabsl (x);
+  long double t2 = t1 / x; 
+  return t2;
+}
+
+/* { dg-final { scan-tree-dump "__builtin_copysignf" "forwprop1" } } */
+/* { dg-final { scan-tree-dump "__builtin_copysign" "forwprop1" } } */
+/* { dg-final { scan-tree-dump "__builtin_copysignl" "forwprop1" } } */
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pr71078-3.c 
b/gcc/testsuite/gcc.dg/tree-ssa/pr71078-3.c
new file mode 100644
index 0000000..8780b6a
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/pr71078-3.c
@@ -0,0 +1,12 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -ffast-math -fdump-tree-forwprop-details" } */
+
+#include <math.h>
+double f(float f)
+{
+  double t1 = fabs(f); 
+  double t2 = f / t1;
+  return t2;
+}
+
+/* { dg-final { scan-tree-dump "__builtin_copysign" "forwprop1" } } */

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